Infix arrow operator.
x y is by default interpreted as DownArrow[x, y].
Used to indicate monotonic decrease to a limit.
Sometimes used for logical nor.
Sometimes used in prefix form to indicate the closure of a set.
See Section 3.10.4.
See also: \[DownTeeArrow] , \[DownArrowBar] , \[DoubleDownArrow] , \[LeftDownVector] , \[UpArrow] .